1. Field of the Invention
The present invention relates to a rotary sinker, a knitting machine, and a stitch forming method.
2. Description of the Related Art
In a knitting machine, a sinker is arranged between knitting needles. The sinker is a different component from the knitting needle and has a function of mainly holding a knitting yarn during formation of a stitch. A known conventional sinker is arranged to reciprocate, as described in U.S. Pat. No. 7,870,760. The conventional sinkers are arranged on both sides of a rotor as a stitch forming portion, and operate by reciprocating to hold the knitting yarn caught by the rotor and remove a stitch thus held from the rotor.
Also, Japanese Patent No. 3192202 describes a stitch forming method in a plain stitch knitting machine. In this method, the knitting machine is arranged, when a first stitch-forming needle catches a fed yarn, not to catch the fed yarn by the next stitch-forming needle. In this arrangement, the fed yarn is directly fed to a hook of the stitch-forming needle without being bent after a yarn-feeding portion.
Recently a technique has been demanded for forming a stitch by a knitting yarn made of low stretch fiber such as carbon fiber. According to the technique of U.S. Pat. No. 7,870,760, a new loop can be easily drawn by an old loop. Therefore, this technique is not suitable for knitting the low stretch fiber. The new loop and the old loop are loops formed by the knitting yarn drawn by the rotor when a stitch is formed by the knitting machine. The loop drawn by (caught by) the rotor is the new loop. When the new loop gets away (goes out of) from the rotor, the new loop is changed into the old loop. According to the technique of Japanese Patent No. 3192202, a yarn which can be easily cut, such as soft twist yarn, is considered. However, since this technique is for knitting machines using the stitch-forming needle, it cannot be applied to a knitting machine using a rotor for stitch formation. Accordingly, there is an unmet demand for a technique which can form a stitch even with a knitting yarn made of low stretch fiber in the knitting machine using the rotor for stitch formation.